Ultrasound (US)-guided axillary nerve block (ANB) may offer adequate analgesia for the nonoperative management of distal radius fractures in the emergency department, according to a study published in the Journal of Orthopaedic Trauma.

Although fracture hematoma block (FHB) is commonly used for pain management during closed fracture reduction, FHB may not offer complete analgesia and has variable efficacy. Investigators hypothesized that the recent increase in the use of US-guided peripheral nerve blocks (eg, ANB and cubital nerve block [CNB]), which are safe and readily available, could be leveraged to improve pain management during closed reductions.

A total of 110 participants who presented to the emergency department and selected for the nonsurgical closed reduction of distal radius fractures were enrolled in 1 of 2 randomized controlled trials (RCTs). In the first RCT (NL56606.098.16), which was conducted between May and November 2016, 50 adults were randomly assigned to receive FHB (mean age, 69.24; 84% women) or CNB (mean age, 66.20; 84% women) prior to reduction. In the second RCT (NL59513.098.16), which was performed between November 2016 and June 2017, 60 adults were randomly assigned to receive CNB (mean age, 72.80; 83% women) or ANB (mean age, 65.27; 83% women).

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The study’s primary outcome was the reduction in pain intensity assessed using a 0 to 10 numeric rating scale; secondary outcomes were pain levels at other stages of the treatment process. A clinically relevant difference in pain intensity was defined as ≥2 points on the scale. All study participants were given 1 g oral acetaminophen for initial management of pain ahead of receiving any block. Block effectiveness was assessed 15 minutes after intervention.

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In the first RCT, patients administered CNB vs FHB  reported lower levels of pain during closed fracture reduction (P =.00001), block administration (P =.002), finger trap traction (P =.007), and after both plaster cast application and control radiography (P =.01 for both). In the second RCT, patients receiving ANB vs CNB reported lower pain intensity during reduction (P <.0001), block application (P =.04), finger trap traction (P <.0001), and after both cast application (P =.0001) and control radiography (P =.0005).

Study limitations include the lack of blinding, treatment by different physicians, the possibility of an inadequate induction period before assessing block efficacy, and a lack of specific standardized block techniques.

“In conclusion, ANB provides more optimal analgesia for nonoperative management through closed reduction of distal radius fractures in adults. A steep learning curve for the

technique, low complication rate, and low costs make this technique suitable for widespread use,” noted the study authors. They recommended that future research explore adequate block placement and induction periods, as well as review resource utilization.

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Siebelt M, Hartholt KA, Winden DFV, et al. Ultrasound-guided nerve blocks as analgesia for non-operative management of distal radius fractures, two consecutive randomized controlled trials. J Orthop Trauma. 2019;33(4):e124-e130. doi:10.1097/bot.0000000000001388